Circulating lncRNA Landscapes: Redefining Biomarker Discovery in Ovarian Cancer

Ovarian cancer (OC) is an aggressive disease with nonspecific clinical manifestations that is frequently diagnosed at advanced stages, drastically reducing the 5- year survival rate, due in part to the absence of specific biomarkers. Owing to its high sensitivity and reproducibility, low cost, and minimal invasiveness, liquid biopsy is a promising technique for OC. Although proteins, ctDNA, and miRNAs have been widely studied as biomarkers, lncRNAs are more advantageous due to their cell- and tissue-specific expression and high stability. Several lncRNAs with potential as liquid biomarkers in OC have been characterized, but none are currently used clinically. The study has analysed 662 lncRNAs deregulated in OC to determine their ability to be detected in biofluids. Twenty-three have been identified in blood samples, four in ascites, and twenty- seven in extracellular vesicles isolated from biofluids. Most of these lncRNAs have an oncogenic role and have been associated with poor prognosis, primarily overall survival. Regarding their diagnostic value, some have even been positively associated with FIGO stages, but only one, included in the panel RP5-837J1.2/miR-361-3p/PELI3, allows differentiation between patients in early stages and healthy women. Information on lncRNAs detected in biofluids related to cancer hallmarks has also been included to identify gaps in the field and to serve as a guide for future research.